The investigators participating in this Program Project Grant are united by interests in the cellular mechanisms underlying the heart.s response to ischemia-reperfusion. The Cell Culture Core Unit will promote the objectives of the research program by providing isolated cardiac myocytes and fibroblasts required by each Project for investigation of G protein-coupled receptor regulation, intracellular signaling, and mitochondrial function. This Core will also performed specific experimentation for each Project and house the equipment and technical expertise required for in vitro studies of hypoxia-reoxygenation.